Form, fill and seal packaging machines to form fluid filled containers from a tube of flexible packaging material are known in the art. For example, U.S. Pat. No. 4,747,253 to Schulte discloses an apparatus for the proportion of the contents during the manufacture of packing containers. The apparatus includes a filling tube extending into a tube of laminated packaging material to deliver milk into the tube of packaging material. A sealing mechanism below the filling tube forms transverse seals across the tube of packaging material to divide the tube of packaging material into individual cushion-shaped packing containers. Cuts are then formed along the seals to separate the individual packing containers. A gas feed pipe is connected to the filling tube to introduce gas into the tube of packaging material to express air before the individual packing containers are formed so that introduced gas is trapped in each packing container as it is formed. The amount of gas introduced into the tube of packaging material is the same as the volume of the air space provided in the individual packing containers. Unfortunately, gas and/or air in the packing container tends to decrease product life.
An alternative apparatus to form fluid filled containers is disclosed in International Application No. PCT/CA96/00783 published on Jun. 5, 1997 under publication No. WO 97/19852 for an invention entitled "Container With Dispensing Spout and Method for Making Same" and assigned to the assignee of the present invention. Each fluid filled container formed by the apparatus includes a body defining an internal reservoir and a narrow, integral dispensing spout extending from the body. The apparatus includes a filling tube extending into a tube of packaging material to delivery fluid into the tuber of packaging material. A heat sealing mechanism having upstream and downstream heat sealing bars forms spaced, curvilinear heat seals across the tube of packaging material defining opposed sides of a container. A fluid displacement mechanism in the form of a cylindrical bar is associated with each heat sealing bar.
In operation, a heat seal is initially formed at the bottom of the tube of packaging material allowing fluid to be delivered into the tube of packaging material via the filling tube. The fluid level in the tube of packaging material is set above the heat sealing bars to that when the curvilinear seals are formed across the tube of packaging material, the resulting containers are filled with fluid and void of air or other gasses. Once fluid has been delivered to the tube of packaging material, the fluid displacement mechanism associated with the downstream heat sealing bar is brought into contact with the tube of packaging material to displace fluid upwardly. The downstream heat sealing bar is then brought into contact with the tube of packaging material to form a heat seal thereacross through the fluid in the tube of packaging material. The heat seal is then cut to separate the container from the tube of packaging material.
Thereafter, the fluid displacement mechanism associated with the upstream heat sealing bar is brought into contact with the tube of packaging material to displace fluid upwardly. The upstream heat sealing bar is then brought into contact with the tube of packaging material to form a heat seal thereacross and the heat seal is cut to separate the container from the tube of packaging material. Once this has been done, the tube of packaging material is indexed and the process is performed again to form successive, alternatively oriented, interlocked, fluid filled containers. The fluid displacement mechanisms displace sufficient fluid prior to forming the heat seals so that the containers can be made self-supporting and so that the volume of fluid in each container is generally less than or equal to the volume of the reservoir. In this manner, the spouts can be devoid of fluid allowing the spouts to be folded over and releasably attached to the bodies.
Although this container forming apparatus overcomes problems associated with conventional container forming apparatuses by forming fluid filled containers devoid of air or other gasses, which extends product life, improvements to container forming apparatuses are continually being sought.
It is therefore an object of the present invention to provide a novel container forming apparatus and method.